EP0245461A1 - Procede de fabrication de supports d'enregistrement optique - Google Patents

Procede de fabrication de supports d'enregistrement optique

Info

Publication number
EP0245461A1
EP0245461A1 EP19860907123 EP86907123A EP0245461A1 EP 0245461 A1 EP0245461 A1 EP 0245461A1 EP 19860907123 EP19860907123 EP 19860907123 EP 86907123 A EP86907123 A EP 86907123A EP 0245461 A1 EP0245461 A1 EP 0245461A1
Authority
EP
European Patent Office
Prior art keywords
rings
composition
substrate
column
master mold
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19860907123
Other languages
German (de)
English (en)
Inventor
Michael Long
Richard Martin Smith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Publication of EP0245461A1 publication Critical patent/EP0245461A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/0038—Moulds or cores; Details thereof or accessories therefor with sealing means or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32—Component parts, details or accessories; Auxiliary operations
    • B29C43/34—Feeding the material to the mould or the compression means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D17/00—Producing carriers of records containing fine grooves or impressions, e.g. disc records for needle playback, cylinder records; Producing record discs from master stencils
    • B29D17/005—Producing optically read record carriers, e.g. optical discs

Definitions

  • the present invention relates generally to record media useful in optical writing and reading of high—density information, and more particularly to improved fabrication methods for optical disks.
  • optical disk technology employs disk elements with spiral or concentric tracks of minute, optically detectable marks (usually on the order of 1 urn or less in size).
  • One real-time mode of recording (writing) such marks is by scanning tracks on the disk with an equivalently small beam of radiation (e.g., from a laser), which is modulated "off” or “on” according to an electrical signal representative of the information to be written.
  • Information is recovered (read) by scanning the tracks with a larger, but still very tightly focused, radiation (e.g., light) spot.
  • the recovered information is in the form of a fluctuating electrical signal obtained from a photodetector that senses the read-out light reflected from the recorded disk.
  • Fig. 1 is a cross-sectional view of a portion of a typical prior-art optical write—and—read recording disk assembly 10.
  • Each disk assembly has a transparent substrate 12 coated on one side with a primer layer 14 and a featured (i.e., having a pattern of depressions and/or protuberances) molded sub—layer 16. The ridges and grooves of this sublayer define the tracks along which the information is recorded.
  • a thin, reflective metal mirror coating 18 is applied to molded sub—layer 16 so that information may be optically recorded onto, and read from, the disk assembly.
  • the mirror coating is in turn coated with a protective layer 20.
  • optical systems of high numerical aperture are used to focus light to small spots.
  • Such optical systems have extremely small depths of focus, and the proper positional relation between the optical system and the record surface of the optical disk assembly must be stringently maintained. Therefore, it is highly desirable that the optical disk assembly support surface underlying the record layer, e.g., the metal coating, be smooth and flat.
  • a liquid composition of acrylate monomers esters of acrylic acid
  • Figs. 2a to 2d illustrate steps in that prior-art process.
  • a few milliliters of the liquid composition (22 in Fig. 2a) are applied to the center of a metal master mold 24.
  • a transparent substrate 12' is placed on the mold such that the space between the master mold and the substrate is filled by a layer of liquid composition 22. This layer is exposed to ultraviolet radiation (Fig. 2c) to polymerize the composition and form sub—layer 16'.
  • the polymerized composition does not adhere to the mold but does adhere to the substrate; and after the exposure, the substrate and the cured sub—layer adhered thereto are removed from the master mold, as shown in Fig. 2d.
  • a reflective metal mirror coating 18 and protective layer 20 (Fig. 1) can then be applied to the sub—layer to complete the disk assembly.
  • the acrylic composition is centrally deposited on the surface of the master mold, and is spread over the master mold when a substrate is pressed against the composition.
  • the flexible substrate may be spherosymmetrically vaulted before being pressed against the composition, whereby the composition is rolled out over the master mold surface while the vaulted substrate is deformed to a planar configuration.
  • the liquid is then cured, and the substrate and attached cured acrylic composition are removed from the master mold.
  • the above-noted molding technique may be •effective to inhibit air entrapment in the composition, but it requires that the substrate be flexible. It has, however, been discovered that rigid disks (made of, for example, aluminum) provide desirable characteristics when used as substrates for optical disk assemblies. See commonly assigned U.S. Patent No. 4,619,804. Preforming the substrate into a spherosymmetrically vaulted form is inappropriate for substrates of rigid material, and other means for inhibiting air entrapment are required. Disclosure of Invention
  • the method of the present invention entails making an optical write—and—read recording disk medium by applying to a substantially flat disk substrate a thin uniform layer of fluid composition between radially inner and outer boundary control rings which repel the composition.
  • a circular bead of the composition is injected into a gap established between a surface of the disk substrate and an opposing surface of a master mold.
  • the composition is applied at a radius such that the surface area of the disk substrate between the inner boundary control ring and the radius is approximately equal to the surface area of the disk substrate between the radius and the outer boundary control ring.
  • the gap between the substrate and the mold is closed such that the fluid composition spreads radially inwardly and outwardly from the circular bead to the inner and outer boundary control rings, which slow the advance of non-uniform fronts of the composition and allow those fronts to equalize.
  • the boundary control rings are made of silicone and are screen—printed on the operative surface of the master mold. Such rings also may act as reservoirs to accommodate any surplus composition.
  • Fig. 1 is a fragmental sectional view of an optical disk assembly in accordance with the prior art
  • Figs. 2a—2d are a series of fragmental sectional views illustrating a prior—art process for making optical disk assemblies
  • Fig. 3 is a perspective sectional view showing one step of a process for making single-sided optical disk assemblies in accordance with the present invention
  • Fig. 4 is an enlarged, fragmental, perspective sectional view of mold structure depicted in Fig. 3; and Fig. 5 is an exploded perspective view of apparatus partially shown in Fig. 3.
  • Fig. 3 best illustrates the basic features of this invention.
  • the manufacturing method described herein presents a process for making optical disk assemblies by molding a radiation—curable plastic sub—layer onto a substrate disk.
  • This process involves placing a clear glass master mold in spaced alignment with the substrate, injecting a viscous, radiation—curable, fluid composition between the master mold and the substrate disk, spreading the composition uniformly and without defect over the substrate disk, exposing the composition to radiation, and delaminating the master mold from the disk, leaving the sub-layer bonded to the disk. Metal and other layers may be coated over the sub-layer to complete the disk assembly.
  • a master mold 26 consists of a flat glass plate.
  • One surface (the bottom one in Fig. 3) 28 of master mold 26 has been ground and polished, preferably to a finish with defects no larger than about 10 to 15 A RMS and scratches no wider than 0.0254 ⁇ m.
  • the smooth surface may have data or formatting information etched therein. Details of a preferred method for manufacturing the master mold can be found in the aforementioned U.S. Patent No. 4,619,804. The molding technique in accordance with the present invention is described with reference to Fig. 3.
  • a master mold 26 is positioned opposite to a substrate disk 30 such that parallel surfaces of the master mold and the substrate are closely spaced to form a uniform gap.
  • a nozzle 32 extends into the gap to deliver a circular bead 33 of photopolymer between the master mold and the substrate. Details of the nozzle are set forth below with reference to Fig. 5.
  • the circular bead is formed when the nozzle moves in a circular path within the gap.
  • the nozzle can be held stationary and the master mold and substrate rotated about their common axis. With the correct gap, photopolymer pumping rate, and nozzle tip volecity, the photopolymer wets both the surface 28 of the master mold and the opposing surface of the substrate to form a uniform annular column 33 suspended between the master mold and substrate surfaces due to capillary action.
  • Suspension of the column allows the bead of photopolymer to cling to both surfaces while it is fluid, thus inhibiting any trapping of small air bubbles in the photopolymer between the two surfaces.
  • a photopolymer whose viscosity is in the 100-150 cp range, having contact angles with the substrate and master mold of about 25 to 40 indicate that the column can be reliably established and maintained if the separation between the master mold and substrate surfaces is less than about 0.25 cm.
  • the ratio of the nozzle tip velocity in centimeters per second to the photopolymer delivery rate in cubic centimeters per second should not exceed about 31 to 1.
  • the photopolymer column is formed at a radius such that the surface area between a predetermined inside diameter to which the photopolymer is to be spread and the photopolymer column is approximately equal to the surface area from the photopolymer column outwardly to an outside diameter to which the photopolymer is to be spread.
  • Spacer rings 34 and 36 have been provided at those inside and outside diameters.
  • Delivery of the photopolymer along nozzle 32 may be effected by any suitable mechanism.
  • the presently preferred method is to provide a syringe driver, not shown, to meter a precise volume of photopolymer at a flow rate synchronized with the angular velocity of the nozzle relative to the master mold and substrate.
  • the nozzle is withdrawn.
  • the gap is then closed, forcing the photopolymer column to be flattened such that the photopolymer composition spreads radially inwardly and outwardly from the column to form a uniform, defect—free film.
  • Boundary control rings 34 and 36 inhibit photopolymer composition runoff at the inside and outside diameters, provide a uniform gap, and act as reservoirs to accommodate any surplus composition.
  • Boundary control rings 34 and 36 (an enlarged detail of ring 36 is shown in Fig. 4) preferably are screen—printed onto the master mold surface 28.
  • the ring material is selected so as to inhibit composition spread by repelling the composition in a manner similar to the way wax repels water. Silicone is a suitable material for such rings.
  • Rings 34 and 36 are patterned to allow any air pushed ahead of each composition front to escape while restricting passage of the composition itself. By repelling the composition, the rings retard outermost portions of each front while lagging portions catch up, thereby tending to keep both fronts circular as they approach the rings. The composition is thus more evenly distributed over the substrate, and runoff of the composition beyond rings 34 and 36 is prevented.
  • the film is polymerized by exposure to ultraviolet radiation through transparent master mold 26.
  • the radiation source may be a mercury—vapor lamp having a wave length of about 330 nm to 450 nm.
  • the photopolymer composition is formulated to preferably adhere to substrate 30 and become a highly cross-linked solid replicate of the master mold's surface. Upon separation of the master mold from the substrate, the photopolymer does adhere slightly to the master mold, thereby removing any dirt particles which may be present, leaving the master mold clean for the next molding operation. The operation is thus self-cleaning.
  • Fig. 3 shows details of a preferred embodiment of nozzle 32.
  • the nozzle has a seamless, thin-wall, stainless—steel tube 38 attached, by flexible tube 39, to a photopolymer composition delivery system (not shown).
  • Tube 38 is elliptical in cross section, with its major and minor axes oriented during delivery such that the minor axis is in the direction of the gap width. Formation of a photopolymer composition column is aided by the presence of means for causing the composition stream to part as it leaves the nozzle and for causing a portion of the stream to be directed toward the substrate and another portion to be directed toward the master mold.
  • a thin wire 40 across the nozzle tip directs composition exiting from the tip both upwardly and downwardly across the gap between the substrate and the master mold, whereby contact is made with the opposing surfaces thereof to permit capillary action to form the column. Thin wire 40 also allows withdrawal of the nozzle tip from the composition column without causing composition to trail behind the tip.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)

Abstract

Un procédé de fabrication d'un support d'enregistrement et de lecture optique en forme de disque comprend l'application sur un substrat de disque (30) sensiblement plat d'une couche mince et uniforme d'une composition fluide, entre des anneaux intérieur et extérieur de délimitation (34 et 36) qui repoussent la composition. Un cordon circulaire (33) de cette composition est injecté dans un espace créé entre la surface du substrat de disque (30) et une surface opposée (28) d'un moule matrice (26). Le rayon d'application du cordon (33) est tel que la superficie du substrat de disque (30) comprise entre l'anneau intérieur (34) et la rayon est approximativement égale à la superficie du substrat de disque (30) comprise entre le rayon et l'anneau extérieur (36). L'espace entre le substrat (30) et le moule (26) est ensuite fermé de sorte que le cordon de la composition s'étende radialement vers l'intérieur et l'extérieur du rayon, dans la direction des anneaux intérieur et extérieur (34) et 36). Les anneaux retardent et uniformisent ainsi des fronts nonuniformes d'extension de la composition. Les deux anneaux (34 et 36) peuvent être imprimés au cadre en matériaux à base de silicones sur la surface opposée (28) du moule (26).
EP19860907123 1985-11-18 1986-11-07 Procede de fabrication de supports d'enregistrement optique Withdrawn EP0245461A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US79922485A 1985-11-18 1985-11-18
US799224 1985-11-18

Publications (1)

Publication Number Publication Date
EP0245461A1 true EP0245461A1 (fr) 1987-11-19

Family

ID=25175348

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860907123 Withdrawn EP0245461A1 (fr) 1985-11-18 1986-11-07 Procede de fabrication de supports d'enregistrement optique

Country Status (2)

Country Link
EP (1) EP0245461A1 (fr)
WO (1) WO1987002935A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0354742A (ja) * 1989-07-21 1991-03-08 Japan Synthetic Rubber Co Ltd 光ディスク、その製造方法および読み取り方法
DE69211198T2 (de) * 1991-03-26 1996-10-31 Canon Kk Verfahren zum Herstellen von Formteilen aus Kunststoff mit Reliefmustern auf der Oberfläche
EP1031407B1 (fr) 1999-02-23 2002-11-20 OTB Group B.V. Procédé pour la fabrication d'un disque et un disque ainsi produit
CN1262883C (zh) 2000-07-17 2006-07-05 得克萨斯州大学系统董事会 影印用于平版印刷工艺中的自动化液体分配的方法和系统
WO2003020488A1 (fr) * 2001-08-30 2003-03-13 Zeptosens Ag Procede de fabrication de corps moules, en particulier de structures optiques, et leur utilisation
US7090716B2 (en) 2003-10-02 2006-08-15 Molecular Imprints, Inc. Single phase fluid imprint lithography method
US7307697B2 (en) 2004-05-28 2007-12-11 Board Of Regents, The University Of Texas System Adaptive shape substrate support system
US8850980B2 (en) 2006-04-03 2014-10-07 Canon Nanotechnologies, Inc. Tessellated patterns in imprint lithography

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1500698A (en) * 1920-04-10 1924-07-08 Wiehl Alfred Phonograph record and process of making the same
US2499397A (en) * 1945-07-07 1950-03-07 Lyon George Albert Method of and apparatus for forming thin annular plastic articles
GB664730A (en) * 1948-07-20 1952-01-09 Pirelli Improvements relating to the manufacture of moulded articles composed of a plastic, for example elastic rubber
FR1316239A (fr) * 1962-02-27 1963-01-25 Battenfeld Geb Dispositif pour la fabrication de pièces en matière synthétique moulées par pressage
US3485908A (en) * 1966-12-09 1969-12-23 Oliver Tire & Rubber Co Method for molding elongated elastomeric articles
US4257988A (en) * 1978-09-12 1981-03-24 Optical Warehouse Showroom And Manufacturing, Inc. Method and assembly for molding optical lenses
FR2516286A1 (fr) * 1981-11-06 1983-05-13 Thomson Csf Procede d'obtention d'un disque-copie a partir d'une gravure originale portee par une matrice

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8702935A1 *

Also Published As

Publication number Publication date
WO1987002935A1 (fr) 1987-05-21

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